Sulfur tetrafluoride

Sulphur ( IV ) fluoride

Colorless gas with a pungent odor

Gaseous

1.919 g · cm -3 ( liquid at -73 ° C)

-121 ° C

-40.4 ° ​​C

10 bar (20 ° C)

Decomposes in water with vigorous reaction

Risk

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Sulfur tetrafluoride is a chemical compound selected from the group of inorganic sulfur compounds and fluorides.

History

Sulfur tetrafluoride was discovered in 1929 by Joseph Fischer and Werner Jaenckner. The representation achieved from cobalt (III ) fluoride, and sulfur, wherein the reaction mixture in order to reduce the reactivity of fluorspar was added. The resulting Schwefeltetraflourid they condensed in liquid air.

Production and representation

Sulfur tetrafluoride is produced by direct fluorination of sulfur or fluorine. Instead of fluorine, the use of trichlorofluoromethane is possible.

In the laboratory, it may also be prepared by the reaction of sulfur with sodium fluoride ( or in addition to chlorine).

Properties

Sulfur tetrafluoride is a colorless, non-flammable gas with a pungent odor. It decomposes in water with a violent reaction, and when heated, with hydrogen fluoride is formed. It has a critical temperature of 91 ° C, the triple point is at a temperature of -121 ° C and a pressure of 1.7 mbar. It acts as a weak Lewis acid to form, for example, 1:1 adducts with organic bases such as pyridine and triethylamine.

Structure

Sulfur tetrafluoride has in addition to its fluoro a nonbonding pair of electrons and thus forms an overall - on the axial positions related - distorted trigonal bipyramid. The lone pair of electrons occupies this one of the three equatorial position and two fluorine substituents the other two. In the 19F NMR spectrum is, however, only a single F signal observed at room temperature, since all fluorine atoms to quickly change places.

Use

Sulfur tetrafluoride is used as a fluorinating agent of inorganic oxides, sulfides or carbonyls or particularly the keto C = O to CF2.